218406945 has 16 divisors (see below), whose sum is σ = 352913472. Its totient is φ = 115329600.

The previous prime is 218406943. The next prime is 218406953. The reversal of 218406945 is 549604812.

It is not a de Polignac number, because 218406945 - 2¹ = 218406943 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (218406943) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 70567 + ... + 73596.

It is an arithmetic number, because the mean of its divisors is an integer number (22057092).

Almost surely, 2^218406945 is an apocalyptic number.

It is an amenable number.

218406945 is a deficient number, since it is larger than the sum of its proper divisors (134506527).

218406945 is a wasteful number, since it uses less digits than its factorization.

218406945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 144272.

The product of its (nonzero) digits is 69120, while the sum is 39.

The square root of 218406945 is about 14778.5975315657. The cubic root of 218406945 is about 602.2204254924.

The spelling of 218406945 in words is "two hundred eighteen million, four hundred six thousand, nine hundred forty-five".